STUDIES ON THE ANTI-BACTERIAL ACTIVITY OF DOXYCYCLINE

Abstract

1) The newly isolated 55 strains including 32 gram (+) cocci and 23 gram (--) rods were tested for the sensitivity to TC and DOTC. From the results obtained concerning MIC value, DOTC, showed more active than TC especially in the former group including Staphylococcus aureus strains.
2) The TC and DOTC serum levels after each single oral administration of 1, 000 mg and 200 mg respectively were measured by modified standard method of Pfizer Laboratory, and also antistaphylococcal activity of these sera were analyzed by their effects on the growth curve of 209 P strain automatically recorded by biophotometer (Jouan).
From the results, it was demonstrate d by both methods that DOTC appears in serum earlier than TC, and smaller dose is sufficient enough to obtain an effective concentration there than TC.